Hysterosalpingogram (HSG): What the Test Shows and What to Expect
Key Takeaways
An HSG is an X-ray test that shows the shape of the uterine cavity and whether contrast passes through the fallopian tubes. It can identify an obstruction, but a normal result does not exclude every form of tubal disease. Discomfort usually peaks while the contrast is injected, and trials have not shown clear benefit from the oral painkillers commonly taken beforehand.
Key evidence: Cochrane — Tubal flushing for subfertility (2020) Cochrane — Pain relief in hysterosalpingography (2015) Swart et al. — Accuracy of HSG in tubal pathology, meta-analysis
On this page
- What an HSG is — and what it is not
- When in your cycle the test is done
- What actually happens during the test
- Does an HSG hurt?
- What an HSG can show — and what it cannot
- Dr. Aksoy’s Approach
- Can the test itself improve your chances?
- What an abnormal result usually means next
- FAQ
- Sources
What an HSG is — and what it is not
A hysterosalpingogram is an X-ray test. Dye passes through the cervix into the womb. A short series of images then shows where it goes. The dye should fill the womb, travel through both tubes and spill into the abdomen. HSG stands for hysterosalpingography — hystero for womb, salpingo for tube and graphy for imaging.
An HSG is a diagnostic test, not a treatment. It produces images of the uterine cavity and fallopian tubes; it does not repair a blockage. Tubal flushing may affect the chance of conception in a selected group, as discussed below, but that is not the main reason for ordering the test.
An HSG looks inside two spaces: the cavity of the uterus, and the channel inside each tube. It does not show the outside of the tubes, the ovaries, or the pelvic lining.
When in your cycle the test is done
The test is normally booked in the first half of the cycle, after bleeding has stopped and before ovulation — commonly somewhere between day five and day twelve of a 28-day cycle.
Bleeding can make the images harder to interpret. Testing before ovulation also reduces the chance that an early pregnancy is already present, which matters because the test uses X-rays. If your cycles are irregular, the clinic will usually time the test according to when bleeding starts and stops rather than to a calendar date.
What actually happens during the test
The appointment is short. The imaging itself usually takes a few minutes; most of the visit is preparation, positioning and waiting. Expect the whole visit to run longer than the procedure.
You lie on an X-ray table. A speculum is placed, the cervix is cleaned, and a thin catheter is passed through the cervical canal. Contrast is injected slowly, and images are taken as it moves. The speculum is then removed, and you can usually get up straight away. Mild spotting and cramping afterwards are common, and a small amount of contrast may leak for a day.
Does an HSG hurt?
Most people feel a strong cramp for a short time, not steady pain throughout. Pain usually peaks when the dye enters and stretches the womb. In a trial of three ways to relieve pain, this step scored highest. Average scores were about 5 to 7 out of 10, depending on the method used.[1]
A Cochrane review of 23 trials in 1,272 women found no clear benefit from oral non-opioid painkillers such as ibuprofen or paracetamol during the procedure (mean difference −0.13, 95% CI −0.48 to 0.23; 3 studies, 133 women; low-quality evidence).[2] Topical anaesthetic applied to the cervix before the test produced a modest reduction in pain, although this evidence was also rated low quality (mean difference −0.63, 95% CI −1.06 to −0.19; 9 studies, 613 women).[2]
Intravenous opioids reduced pain in some trials, but they can cause adverse effects and require a longer recovery.[2]
In practice, ask whether your clinic offers local anaesthetic and keep expectations modest for an oral painkiller taken beforehand. Knowing when discomfort is most likely can make the test feel more predictable.
What an HSG can show — and what it cannot
A normal HSG does not exclude every tubal problem, while an abnormal result may still need confirmation.
Pooled data from 20 studies in 4,179 women compared HSG with keyhole surgery and dye.[3] HSG had a sensitivity of about 0.65 and a specificity of about 0.83 for showing an open tube. It can therefore miss disease. A blockage seen near the womb can still be due to a brief spasm. HSG is also poor at finding scar tissue around the tubes.[3]
| What you want to know | How well HSG answers it |
|---|---|
| Is a tube blocked? | An apparent blockage is informative, but proximal spasm can mimic one |
| Are the tubes definitely healthy? | No — a normal result does not exclude every tubal abnormality |
| Is there scarring around the outside of the tubes? | Not reliable |
| Is the uterine cavity an abnormal shape? | It outlines the cavity, but a suspected abnormality may need ultrasound or MRI for clarification |
| Is there endometriosis? | No — HSG cannot see peritoneal disease |
Endometriosis affects tissue outside the uterine cavity and tubal lumen, which HSG does not image. Distorted anatomy may raise suspicion, but HSG cannot diagnose or exclude the condition.
A tube can also appear blocked when it is not. Spasm at the point where the tube meets the uterus can stop contrast passing on the day, and a repeat test or a different method sometimes shows an open tube.
Dr. Aksoy’s Approach
A normal HSG shows that dye passes through the channel inside the tube. It does not prove that the tube works well. The fringed end may not collect the egg, the tiny hairs inside may not move well, or fine scars may sit around the tube. HSG can also miss mild endometriosis. That is why I do not read the word “normal” on its own.
I accept a normal HSG when the history does not point to disease in the tubes or pelvis. This means no past pelvic infection or chlamydia, ectopic pregnancy or pelvic surgery. There should also be no marked period pain, pain during sex or ovarian endometrioma. The images must be clear, with dye spilling quickly and freely from both tubes.
I investigate further only when the answer could change treatment. Delayed or loculated spill, a suspected hydrosalpinx, or a strong history of endometriosis or adhesions would prompt me to look further. By contrast, for an older patient or one with low ovarian reserve, a minor finding may not change the plan. In that situation, I would rather move to IVF than spend months on diagnostic laparoscopy.
This clinical approach was recorded on 18 August 2026 and reviewed against ASRM guidance on fertility evaluation.[4]
Can the test itself improve your chances?
There may be a fertility benefit, but it applies to a specific group and the evidence has important limits.
Doctors noticed decades ago that some women conceived soon after tubal flushing. A 2020 Cochrane review of 15 trials in 3,864 women compared oil-based dye with no treatment.[5] Oil-based dye was linked to better odds of live birth. However, the evidence was low quality, and the live-birth estimate came from only 204 women.
The largest single trial is more informative. In 1,119 women across 27 Dutch hospitals, ongoing pregnancy within six months was 39.7% after oil-based contrast versus 29.1% after water-based, and live birth was 38.8% versus 28.1% (rate ratio 1.38, 95% CI 1.17 to 1.64).[6] Adverse event rates were low and similar in both groups.
One detail limits how broadly this result can be applied. Participants were initially managed expectantly or with intrauterine insemination; IVF was not the planned treatment pathway, although a small minority underwent IVF or ICSI during follow-up. The trial therefore does not establish a benefit for women proceeding directly to embryo transfer.[6]
The result does not apply to every patient. A 2026 H2Oil2 preprint has not yet been peer reviewed.[7] It studied 932 women who were aged 39 or older, had an ovulation problem or had a high risk of tubal disease. It found no clear live-birth benefit: 23.5% with oil-based dye versus 21.5% with water-based dye. The adjusted hazard ratio was 1.18 (95% CI 0.89 to 1.57).
Any possible fertility benefit must be weighed against safety. Oil-based dye contains a large amount of iodine. One study followed pregnant women who had this type of HSG before conception.[8] Iodine excess was found in 38 of 70 women. Of those 38, 25 (65.8%) had an underactive thyroid with or without symptoms. Two had excess thyroid hormone, called thyrotoxicosis. No thyroid problem was found in their babies.
Intravasation — contrast tracking back into blood or lymphatic vessels — can occur with either oil- or water-based contrast. Most reported cases cause no embolic symptoms, while rare case reports describe suspected embolic complications.[9]
For the right patient, oil-based contrast may be reasonable; it should not be an automatic choice.
The official product information calls for slow injection in 2 mL increments under fluoroscopic control, stopping immediately if intravasation is suspected or confirmed.[10] Excessive injection pressure is a recognised risk factor for intravasation and is therefore avoided.[9]
What an abnormal result usually means next
An abnormal HSG is usually the start of a more specific assessment.
If one or both tubes do not fill, the next question is whether this reflects a true blockage, spasm on the day, or disease further along the tube. When the apparent block is at the point where the tube meets the uterus, repeat imaging or selective tubal cannulation may be considered before laparoscopy.[11]
If a tube appears dilated and does not spill, the finding may be a hydrosalpinx. A communicating hydrosalpinx can reduce IVF pregnancy rates, so it may change what is done before embryo transfer.[11] If there has been a previous pelvic infection, salpingitis may explain the damage seen on the images.
For most patients, HSG is the first-line test. Laparoscopy may be considered first when there is strong suspicion of endometriosis, hydrosalpinx, peritubal adhesions, or damage after infection or surgery, particularly if treatment could be carried out in the same session.[4]
Hysteroscopy is not an alternative to HSG. It assesses the uterine cavity, not the outside of the tubes or the pelvis. It is used when ultrasound or HSG suggests a cavity abnormality, when there is abnormal bleeding, or when intrauterine surgery is needed.
Bring the original images or report to any new consultation. Reviewing them may help avoid an unnecessary repeat test.
FAQ
What does HSG stand for?
Hysterosalpingography. The parts of the word describe the test: hystero means uterus, salpingo means fallopian tube, and graphy means imaging. Some clinics call it a tubal patency test or a uterotubal X-ray.
Is an HSG a treatment for blocked tubes?
Its main purpose is diagnosis, not repairing a blocked tube. Oil-soluble contrast may have a fertility benefit in selected groups, but the evidence has limits.
How long does an HSG take?
The imaging itself usually takes a few minutes. Plan for the whole appointment to take longer because it also includes preparation, positioning and a short period of rest afterwards.
When in my cycle should the test be booked?
Usually after bleeding has finished and before ovulation, often between roughly day five and day twelve of a 28-day cycle. The timing avoids blood obscuring the images and reduces the chance that an early pregnancy is present.
Can an HSG detect endometriosis?
No. An HSG images the uterine cavity and the channel inside each tube. Endometriosis affects tissue outside these spaces. Distorted anatomy can raise suspicion, but HSG cannot diagnose or exclude the condition.
Does a normal HSG mean my tubes are fine?
Not entirely. Against laparoscopy as the reference standard, HSG has limited sensitivity for tubal patency. A normal result is reassuring, but it does not exclude every form of tubal disease.
Why did the test show a blockage when a later test did not?
Spasm where the tube joins the uterus can prevent contrast passing on the day, producing the appearance of a blockage in a tube that is actually open. This is one reason a single abnormal finding is often rechecked before any surgical decision is made.
Sources
- Babandi RM, Agboghoroma OC, Durojaiye KW, Jimoh KO, Essiet EA. Pain relief for hysterosalpingography: a randomized controlled, double blinded trial comparing suppository diclofenac, prilocaine/lignocaine (EMLA) cream and placebo. West Afr J Med. 2021;38(12):1174–1182. PubMed
- Hindocha A, Beere L, O’Flynn H, Watson A, Ahmad G. Pain relief in hysterosalpingography. Cochrane Database Syst Rev. 2015;(9):CD006106. PubMed · doi:10.1002/14651858.CD006106.pub3
- Swart P, Mol BW, van der Veen F, van Beurden M, Redekop WK, Bossuyt PM. The accuracy of hysterosalpingography in the diagnosis of tubal pathology: a meta-analysis. Fertil Steril. 1995;64(3):486–491. PubMed · doi:10.1016/S0015-0282(16)57781-4
- ASRM Practice Committee. Fertility evaluation of infertile women: a committee opinion (2021). ASRM
- Wang R, Watson A, Johnson N, Cheung K, Fitzgerald C, Mol BWJ, Mohiyiddeen L. Tubal flushing for subfertility. Cochrane Database Syst Rev. 2020;10(10):CD003718. PubMed · doi:10.1002/14651858.CD003718.pub5
- Dreyer K, van Rijswijk J, Mijatovic V, et al. Oil-based or water-based contrast for hysterosalpingography in infertile women. N Engl J Med. 2017;376(21):2043–2052. PubMed · doi:10.1056/NEJMoa1612337
- Huijser J, Zhu Q, Kamphuis D, et al. Oil-based versus water-based contrast media during hysterosalpingography for infertility (H2Oil2 study): a randomised controlled trial. SSRN preprint, posted 27 May 2026. SSRN · doi:10.2139/ssrn.6812698 — preprint; not yet peer reviewed.
- Li R, Chen W, Liu Y, Ma L, Qiu L, Han J, Li R. The impact of preconceptional hysterosalpingography with oil-based contrast on maternal and neonatal iodine status. Reprod Sci. 2021;28(10):2887–2894. PubMed · doi:10.1007/s43032-021-00640-0
- Geenen RWF, van der Molen AJ, Dekkers IA, et al. Contrast media for hysterosalpingography: systematic search and review providing new guidelines by the Contrast Media Safety Committee of the European Society of Urogenital Radiology. Eur Radiol. 2024;34:6435–6443. Springer · doi:10.1007/s00330-024-10707-6
- Guerbet. Lipiodol Ultra Fluid: Summary of Product Characteristics. Revised 17 March 2021. Product information
- ASRM Practice Committee. Role of tubal surgery in the era of assisted reproductive technology: a committee opinion (2021). ASRM
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The content has been created by Dr. Senai Aksoy and medically approved.